Adding Metadata To Each Gallery

Got a question, I cover a fair few sports and I'm in the middle of re-designing my gallery themes to match each sport.
One of the reasons is I'll like to add website metadata for each sport, use target keywords for each of those sports in hope of getting new hits on the site.

I've tried to do it through the themes and checked out the source page, only to see that the page metadata is there twice, one with what I added, the other with the basic one from the site.